What IS needed is the ability to evade BVR missiles, the ability to disengage from combat. The F-35 might have the former because of its jamming suite and reduced RCS. It certainly doesn't have the latter two. If you can't disengage, then you need the ability to win a WVR fight.
And you are claiming a platform with no external ordnance, clean as a whistle, with a T/W greater than 1, can't do this?
The acceleration of an F-35 in combat configuration is going to be superior to just about anything out there. And that's not good enough?
Obviously, high off boresight missiles, which everybody will have, help. However, high off boresight missiles aren't a magic aim and shoot weapon.
Actually, they pretty much are. There will be more than enough surplus energy to make the intercept. We considered the AIM-9L to be nearly magical, with a Pk well above 90%.
Thus, getting somewhere in the general direction of the opponents six o clock (to give the missile enough time to maneuver), is still a very useful thing.
No, I'm sorry, there is absolutely no need to get to an opponents six o'clock in anything other than canned or highly unusual circumstances
where both fighters are inside each others' turn circle. Modern IR missiles lock, guide, and fuse all-aspect. If I want to kill that guy 3 miles in front of me, I point and shoot regardless of angle-off. I would be a fool to do any extraneous maneuvering, as there is a strong possibility that he has a friend nearby. My maneuvering would waste precious seconds and expose me needlessly.
As I pointed out, high instantaneous turn rate is misleading. Try turning hard enough with an F-35 to evade multiple missiles and you'll find yourself falling out of the sky.
Ask yourself a question... do you think that you will be visually acquiring a modern AA missile, and further, maneuvering in relation to that missile? If you think this is common or even possible, you have been watching too many movies.
One cannot even see a jet the size of an F-5 when it is nose-on, and the range exceeds 2 miles. If I launch a smokeless AIM-9X at you from 3 miles, do you think you'll pick it up, something that is traveling at mach 3 and is 1/100th the cross-section of an F-5? This notion of BFMing a missile is one of the most common misconceptions out there. If a pilot was actually able to acquire that mach 3 sliver, he'd have about 100 milliseconds before it is on him.
As for the Gulf War, most of the kills were made within visual range. Granted, there wasn't much turning involved, but that isn't surprising given that the Iraqis were usually significantly outnumbered and lacked situational awareness due to not having good ground control or AWACS.
You must learn to differentiate between visual range, and turning circles. Visual range, when aided by AWACS and target designotor boxes, and perhaps by fortunate enemy wing flashes, is anything inside of about 8 to 10 miles. At those distances, the enemy can do 9G turns all day and he'll still be a speck right in front of me. It's technically visual combat where turning does nothing. Between 8 miles and 3,000 meters is a zone between BVR and the turn circle, and is a perfect region for point & shoot kills. THAT is where most kills occurred in GW1.
Dogfighting in the idealized sense rarely ever occurred. Most kills during the World Wars were scored by sneaking up on the opponent. This started to change with the introduction of control radar, and we had significant dogfighting during the Vietnam war, but modern day fights won't last for more than a few turns. However, what is needed is the ability to make those few turns as quickly as possible and to retain enough energy to escape. The F-35 doesn't have that ability.
The only reason turning took place in Vietnam was because the missiles did not support the all-aspect fight. You say, "modern day fights won't last for more than a few turns." In reality, they'd be lucky to make it through 180 degrees before the majority of kills take place. There might be a very rare matured turning fight once in a while. I'd parallel this to two foot soldiers in a knife fight.
Any excess amount of treasure and talent devoted to hyper-maneuverability is like spending billions developing a titanium-carbon superalloy bayonet that costs hundreds of thousands of $$. Irrational and foolish. The F-35 will have turning performance exceeding the F-16, and that is all it needs.